> N[7]:=(xi,eta) -> 9*(1+xi)*(1-eta^2)*(3-2*xi+3*eta)/32;

                                              2
   N[7] := (xi, eta) -> 9/32 (1 + xi) (1 - eta ) (3 - 2 xi + 3 eta)

> plot3d(N[7],-1..1,-1..1,grid=[15,15],axes=boxed,scaling=constrained,
> style=patch,orientation=[-60,60]);

> 
> 
